July 10, 1998, at the Summer
NAMM show in Nashville, Fender will unveil SFX™ (Stereo Field
eXpansion), arguably the most important breakthrough in instrument
speaker technology since the introduction of the Leslie speaker. A bold
statement, perhaps, but the SFX effect simply has to be heard to be
believed. The system is also affordable, adaptable to existing amp rigs
and based on acoustical principles so simple that once the word gets
out, 100,000 audio engineers around the planet are going to kick
themselves, wondering, "Why didn't I think of that first?"

Unfortunately, there's no way to
create a usable stereo field from a standard combo guitar amp, whether
the speakers are side by side or stacked atop each other. Move two
cabinets to either
side of the stage for maximum separation and the audience along the
center
aisle hears the spread, while listeners on either side hear mostly one
side
or the other. Essentially, SFX is a system for creating/playing back
huge
stereo effects from two speakers that are placed near each other, or
within
the same cabinet.

Licensed by Fender, the SFX
system was
developed and patented under the name CPS (Center Point Stereo) by
Groove Tubes founder Aspen Pittman and Drew Daniels, who has served as
AES Chairman in Los Angeles and is an electro-acoustic engineer who has
worked for JBL, Tascam, Fender and Walt Disney Imagineering.

So how does it work? According to
co-inventor Daniels, the process is extraordinarily simple: "The basic
principle is
like M-S [mid-side] miking in reverse." A stereo signal from a guitar
preamp
or effects loop feeds two speakers: One channel is routed through a
sealed
enclosure with its cone facing forward, representing the "mid" part of
the
signal. And like the "side" part of the M-S miking equation, the bottom
speaker
is mounted on a baffle (perpendicular to the top speaker) within an
open-sided enclosure to generate a figure-8 dispersion, where one side
is out of phase with the other.

"The SFX electronics process
stereo signals into sum and difference signals," explains Daniels. The
signals that started out as "left" signals are made into signals that
add acoustically in the air around the cabinet, causing the SFX speaker
array to steer the combined acoustical output of the two speaker
elements toward the left side of the cabinet. Signals originally from
the "right" are made into signals that subtract acoustically, causing
the SFX speaker array to steer the acoustical output toward the right
side of the cabinet.

By simply adjusting the balance
between the two speakers and feeding a stereo source (such as the
onboard DSP effects built into the new Fender amps), a massive ambient
field is formed that
can envelope a medium-sized room. "Hearing SFX is like hearing surround
TV
for the first time," beams co- inventor Pittman. "It makes the amp
sound
huge and not just left/right, but deeper." Pittman does add a warning
about
using the system for the amplification of recorded playback material:
"Compared to ordinary stereo, SFX is not as accurate. However, its
surreal reproduction enhances stereo effect."

At NAMM, Fender will show three
SFX amps: The $999 SFX Keyboard 200 has two stereo and one mono input
for keyboards; the $899 Acoustasonic SFX is designed for acoustic
instruments; and for
players who want SFX but already have a favorite amp, the $749 SFX
Satellite
is an add-on single-12 cabinet with onboard amp and DSP.

While SFX technology is currently
only offered in instrument amps, other applications come to mind,
although large-scale concert P.A. probably won't be among them, due to
the feedback con-siderations of very wide dispersion systems. How-ever,
SFX could be ideal in special
venue or theme park installations, or possibly as a replacement for
cinema
surround speakers. It will be interesting to see where SFX goes next.